In the agricultural industry, it is frequently necessary or desirable to treat the soil with a soil fumigant and/or an herbicide. Soil fumigants are generally designed to sterilize the soil by (1) killing harmful organisms such as nematodes, fungi, bacteria, etc. and/or (2) provoking necrosis in plant tissue to prevent the rapid re-growth of weeds. Topical herbicides are generally designed to eradicate weeds after they have germinated.
Currently, the most effective substance for such a soil fumigant is methyl bromide. However, methyl bromide can be harmful to the nervous system and the respiratory system, and causes depletion of the earth's ozone layer. Methyl bromide is currently being phased out under the so-called Montreal Protocol. The world deadline for total elimination is 2015.
Approximately forty percent of the foliar herbicide used worldwide is paraquat. Paraquat can be fatal if inhaled or if it is absorbed through the skin.
In the agricultural industry, it is also frequently necessary or desirable to control insects and fungi on foliar surfaces/foliage with an insecticide or fungicide. Delivery is generally effected by terrestrial applicators and/or aerial applicators employing conventional flow or fine droplet dispersion.
Currently, the most preferred substances for insect and fungi control are the carbamates. Many carbamates must generally be applied weekly, but their low price can theoretically offset labor rates, whereby to maintain a low total investment in controlling insects and fungi. However, the side effects of their use are now generally acknowledged to affect the health and productivity of the agricultural workers. These side effects include nausea, cramps, diarrheas and flu-like symptoms in agricultural workers. The reduced worker productivity, and the accompanying increased healthcare costs, can make agriculture only marginally profitable in emerging economies. Many carbamate compounds are now under review by the EPA.